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The genetics of the firefly

Researchers are trying to crack the genome of fireflies to use their ability to produce light for medical purposes. The problem is that these wonderful insects are disappearing from the world

fireflies Their lighting mechanism can be used to develop important tools in the field of medicine. Photo: Uqbar is back.
fireflies Their lighting mechanism can be used to develop important tools in the field of medicine. photograph: Sam Weng.

By Racheli Vox, Angle, Science and Environment News Agency

Every year, at the beginning of summer, crowds of people flock to the Great Smoky Mountains National Park on the border between Tennessee and North Carolina in the United States. There, they sit in complete darkness, watching a swarm of fireflies light up the forest. Thousands of small lights turn on and off simultaneously, over and over again, in a synchronized light show. These are fireflies of the species Photinus carolinus, also known as "synchronous fireflies", and this is their courtship season. All the males flash together, bragging to the females, who reply with their own rhythmic flashing. The lucky ones who walk on two who are watching them from the side are treated to a spectacular show, in which thousands of stars seem to shine in all corners of the forest.

Since time immemorial the fireflies have fascinated man with their flying lights in the warm nights. However, their importance to humans is not limited to the visual wonder, and they can also be useful in the development of medical technologies. Today, researchers are trying to map the fireflies' genome, which may lead to uses such as illuminating cancer cells.

One of the most studied firefly species in this context is the Big Dipper, the most common firefly species in North America. Last year, scientists from different universities got together and sent this firefly to the "most interesting genome" competition, held by Pacific Biosciences from San Francisco, and the prize was genome mapping using the company's technology.

The firefly came in second place (after Sedum alfredii, a perennial herb from China that adsorbs metals), but the researchers did not give up. They conducted a crowdfunding campaign, managed to raise the amount they needed to complete the project (ten thousand dollars), and today the genome mapping procedure of the Big Dipper is underway.

identify disease-causing bacteria

The fireflies are a family that belongs to the beetle series. There are more than two thousand species of fireflies in the world, eight of which are found in Israel. The process by which the fireflies light up is called bioluminescence and it is carried out through a lighting organ at the end of their abdomen, where an enzyme called luciferase acts on luciferin - a substance that produces light in reaction with oxygen and while investing energy. This is a particularly efficient light production process, during which almost no energy is wasted on heat production. "The illumination is carried out in order to attract mates, the male and female signal to each other," explains Dr. Netta Dorchin from the School of Zoology at Tel Aviv University and the Steinhardt Museum of Nature. "Each species of fireflies has its own special signaling pattern, so they know how to recognize members of their own species."

The illumination, as expected, is one of the main reasons for the medical importance of fireflies, and mapping their genome allows researchers to better understand the genes involved in its creation. Today, the enzyme luciferase is used for medical purposes, such as for the detection of Bacteria arousing Diseases in food וIdentification infections in the urine. Understanding the genetics of illumination may contribute greatly to the field of non-invasive imaging, for example through revealing the locations and quantities of cancer cells through their illumination.

One of the main difficulties in understanding the firefly genome is that it contains a large amount of segments where the same sequence of DNA repeats itself over and over again. These segments are present in all animals (except those that do not have a cell nucleus), including humans, but unlike "normal" DNA, they do not code for any protein. Some of these segments are "selfish genes", which repeat themselves in the genome in order to increase the chance that they will be passed on to the next generation, but they are apparently "parasites" that have no benefit to the animal. Other repetitive segments are essential structures in chromosomes.

Another challenge for researchers is that fireflies are only active in the summer, so the period during which they can study them is limited.

A girl with a firefly. are disappearing from the environment. Photo: Jim Miles.
A girl with a firefly. are disappearing from the environment. photograph: Jim Miles.

A decrease in the insect population

Until scientists figure out all the details of the firefly genome, we might as well just enjoy looking at them. However, they are really not as easy to find as they used to be. In recent years the fireflies Going and disappear from our districts, mainly from the urban areas, in Israel and around the world. The main reason for this phenomenon is the same reason that is responsible for the disappearance of many species of animals: the destruction of open spaces and the interruption of habitats. Beyond that, fireflies are also harmed by man's use of fertilizers and pesticides, as well as light pollution - the massive use of light by man. It has been proven that the fireflies, whose use of light is such a significant element in their lives, avoid areas with strong lighting, and that exposure to lighting significantly reduced the number of their signals. It is not easy to underestimate the amount of light in the environment, but preventing the leakage of light into the open areas and nature reserves, for example by defining a clear policy to prevent light pollution, will certainly help.

The disappearance of the fireflies is part of a widespread phenomenon of the disappearance of many species of insects. "People notice the decrease in the number of fireflies because they are a phenomenon that is seen, while most other insects are small and no one notices them," says Dorchin. "We are seeing a real decrease in insect populations that results from the continuous destruction of habitats and the accumulation of pesticides, these are things that adversely affect all animals and now it has also reached insects." According to Dorchin, this is nothing less than a catastrophe. "If we want to have fruits and vegetables, whose pollination depends on insects, we should stop destroying the insects," she says. "We need to start doing something about this issue, otherwise beyond the direct harm to the environment we will end up harming ourselves as well."

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